Re: [PATCH] vfio/platform: Remove the ACPI buffer memory to fix memory leak

[Hanjun Guo]

On 2022/11/30 3:52, Alex Williamson wrote:
> On Tue, 22 Nov 2022 19:29:58 +0800
> Hanjun Guo <guohanjun@xxxxxxxxxx> wrote:
>
> > The ACPI buffer memory (buffer.pointer) returned by acpi_evaluate_object()
> > is not used after the call of _RST method, so it leads to memory leak.
> >
> > For the calling of ACPI _RST method, we don't need to pass a buffer
> > for acpi_evaluate_object(), we can just pass NULL and remove the ACPI
> > buffer memory in vfio_platform_acpi_call_reset(), then we don't need to
> > free the memory and no memory leak.
> >
> > Fixes: d30daa33ec1d ("vfio: platform: call _RST method when using ACPI")
> > Signed-off-by: Hanjun Guo <guohanjun@xxxxxxxxxx>
> > ---
> >   drivers/vfio/platform/vfio_platform_common.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> > index 55dc4f4..1a0a238 100644
> > --- a/drivers/vfio/platform/vfio_platform_common.c
> > +++ b/drivers/vfio/platform/vfio_platform_common.c
> > @@ -72,12 +72,11 @@ static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> >   				  const char **extra_dbg)
> >   {
> >   #ifdef CONFIG_ACPI
> > -	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> >   	struct device *dev = vdev->device;
> >   	acpi_handle handle = ACPI_HANDLE(dev);
> >   	acpi_status acpi_ret;
> >   
> > -	acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer);
> > +	acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, NULL);
> >   	if (ACPI_FAILURE(acpi_ret)) {
> >   		if (extra_dbg)
> >   			*extra_dbg = acpi_format_exception(acpi_ret);
>
> An identical change was already posted and accepted into the vfio next
> branch, see:
>
> https://lore.kernel.org/all/20221018152825.891032-1-rafaelmendsr@xxxxxxxxx/
>
> In linux-next as:
>
> e67e070632a6 ("vfio: platform: Do not pass return buffer to ACPI _RST method")

Thanks, I missed this patch, please drop this one.

Thanks
Hanjun